For years, computer-aided ­design (CAD) has been used in the automotive industry to develop prototypes of body styles, as well as to design auto components including engine parts, ­electronics and even tires.

CAD software programs, such as this example called Port Expert from Mastercam, provides performance engine builders an accurate, efficient engine cylinder head porting “tool” on their computer’s desktop, in place of the workbench.

In fact, Dr. Patrick J. Hanratty, an American computer scientist who is known as the “Father of CAD/CAM,” helped pioneer the technology in the automotive industry by developing a software system in the mid-1960s for General Motors to automate repetitive drafting ­designs.

In recent years, the use of computer systems to assist in the development, modification and optimization of a performance engine has made its way into engine shops. One reason is that CAD software provides builders detailed analysis and archived referenced data of the engine’s components that can utilized quickly and efficiently for various racing conditions and environments, as well as performance changes/limitations from the sanctioning bodies your customers compete in.

Most CAD software for engine modifications use either vector-based graphics to depict the objects or raster graphics to display the designed components.

But its more than just viewing part designs on your computer screen. CAD programs allow the user to incorporate drafting of technical images, as well as creating dimensions and tolerances of the components for application-­specific uses.

One of the more popular uses of CAD in engine building today is for improving airflow through ports. For example, a common hands-on method for an engine builder looking to increase performance through the visualization of a port configuration is to make a 3D cast of a port.

After pouring rubber compound into the port and letting it cure, the builder prys out the mold casting to better see what the port actually looks like, or to test it.
Obviously, this can be a time-consuming process that utilizes raw materials. However, virtual CAD programming provides the builder a more high-tech approach by digitally mapping the port with a 3D pinpoint plotting devise and then imports the data into a software program for further testing analysis and ­visualization.

CAD programs are often used in conjunction with CAM programs ­integrated with the shop’s tooling equipment, in this case, a CNC machine. Computer-aided manufacturing (CAM) is defined as the use of computer software to control machine-operated tools in the development and modification of manufactured components. And it’s a growing trend in our industry for a couple of reasons.

For one, CAM is beneficial to the performance industry due to its ability to develop a faster ­production process and enables components and tooling more ­precise dimensions and material consistency.
CAD software is often used in conjunction with CAM-equipped machinery, such as a 5-Axis CNC cylinder head porting machine, offering a shop the precision and speed needed to reproduce cylinder heads with exceptional accuracy – with no handwork needed. Photo courtesy Rottler Manufacturing.

It also gives a shop the opportunity to be a niche supplier of custom performance automotive parts, and even non-automotive parts for other industries.
And, it’s helpful to users by ­reducing waste of components, thereby also reducing energy ­consumption.

Where as hand porting a set of cylinder heads takes skill and expertise to achieve consistency, the CAD program enables the builder to make changes and review the data without having to risk damaging an expensive cylinder head.

And once a performance engine builder has developed a port configuration they are satisfied with on the computer, CAD programming allows the user to digitally map the port and replicate it again and again with near perfect consistency in the remaining ports of the cylinder head using the CNC machinery, providing continuous, accurate results.

Best of all, that port configuration data now saved on the computer can also be modified quickly with the CAD software for different engine designs and applications, allowing the user nearly unlimited configuration tweaks.

Performance manifolds are another component that, to save costs and ­optimize airflow, are ­designed using CAD programming. For more on matching the best manifold to your engine build, check out Larry Carley’s article beginning on page 42 of this issue.

One drawback to the CAD technology is taking the time to learn the software programming. According to those knowledgeable in this field, the learning curve for CAD/CAM is rather steep and typically takes six months to a year before a self-taught user is really competent with the ­design software.

And since some performance builders take a lot of pride in their “hands-on” approach to hand-porting services, they may not be interested in re-learning the work via computer.

But, as the industry looks to increase a younger generation of engine builders, the utilization of more computers in an engine shop could be an attractive draw.

Younger job-seekers familiar with computer-aided component development and design programs that they learned in a technical school could be an asset to your performance shop and help bring in new business and increase profits.

Let’s face it, it’s probably less stressful on a shop owner if an ­employee makes a design mistake on a computer program that can be redone with little harm, than to fritter away a lot of shop time, equipment time and the cost of ruining or ­damaging ­expensive engine ­components and materials.

Plus, it’s less stressful on the ­employee, who doesn’t want the stigma of being the one who ruined a potential performance build for a ­customer.

(Keep in mind, too, that CAD/CAM is not fool proof when it comes to CNC machining. Glitches can still happen that end up incorrectly machining a part or damaging the CNC tooling.)

Another roadblock for this technology in is deciding which CAD software program to purchase that best fits your shop’s needs. Since ours is a vocal industry and many performance builders are helpful in sharing knowledge and their experience, were looking for your input.

If you have used CAD and CAM programs successfully in your engine builds, please let us know which software you prefer.

Or, if you work for a company that provides computer aided design or computer aided manufacturing programs for performance engine builders, email us your contact information to [email protected] that we may use in our ­Engine Builders Performance Buyers Guide, which will be available in the March issue.